Here's a GB game I found, it is essentially Radical Rex with a few differences. Instead of breathing fire, you shoot projectiles (rather slowly I might add). I haven't spent much time and already found a few interesting things. At least I think so.
When moving to the right, your x speed is normally 2 and it drops to 1 every few frames. However if you press right and then the next frame hold L+R, you'll move at 2 constantly without dropping to 1, and you slide along the floor. I haven't found a way to get it to work moving to the left yet.
When moving down slopes, jumping at the right time can prolong your speed a little bit.
In 1-2 if you jump on the nest the very first frame possible, t-rex falls to the floor and when the bird picks you up, he's confused for some reason and takes you into the wall. There's no way to zip or anything that I've found, so instead you just need to jump up out of the wall.
There's also a graphical glitch I found that's very easy to perform. If you press Fire for one frame and then Down for 1 frame after that and let go of down the next frame, the graphics become screwed, giving t-rex the wrong sprites and making other sprites scrambled as well. I don't see any particular use for it, but I used it on the first boss just to show it off. It probably cost a few frames to do so, I haven't really checked.
On world 2 the skateboards can be sped up by minimum jumping as soon as you land on them. You jump off faster than you normally ride the skateboard and when you land, if you're close enough, you pull the skateboard to you. You can repeat that until you have to ditch the skate board. Also when jumping off a skateboard, if you press left for one frame and then resume pressing right, your speed will increase to 5 for a few frames, when normally 4 is the max you'd get.
Anyway, I still dunno if this is a good game choice or not, there's a lot of slow movements even though the downhill parts are somewhat fast. I think the later levels would be more interesting, difficulty wise and it wouldn't be too hard to TAS up to. The game is fairly simple. Anyway, I'll let you judge: